In recent years, sexually transmitted diseases have become an increasing medical problem and concern throughout the world. The HIV/AIDS epidemic over the last decade or so has significantly and dramatically underscored the threat of STDs to the human population. Until there is a cure, or at least an effective treatment, the best, and perhaps only realistic, approach to this increasing problem of STDs (especially HIV/AIDS) appears to be reducing the risk of transmission of STDs by the STD-causing organisms and thus reducing the number of individuals who become newly infected. Even when treatments or cures become available, prevention of infections in the initial instance will likely remain as the first line of defense. For economic, medical, and psychological reasons, it is preferable to prevent the initial infection rather than treating, and even curing, individuals with STDs.
At present, education in regard to STDs, their modes of transmission, and so-called “safe-sex” techniques has, at least to some degree in the more developed countries, shown promise in reducing the risks of STD transmission through sexual activity. Screening of the blood supply has helped to reduce the risk of transmission of such STD-causing organisms via blood transfusions and related medical practices. Nonetheless, the spread of such STDs has not been halted to a satisfactory degree even in developed countries with active and progressive education programs. Even with their known effectiveness in preventing STDs, current safe-sex techniques are not always used, or are not always used properly, for many reasons (e.g., carelessness, lack of knowledge, improper techniques, cultural barriers, unplanned or spontaneous sexual activity, and the like). Moreover, even when used, safe-sex techniques (except perhaps abstinence) are not always effective. For example, condoms are generally only about 90 percent effective in preventing conception when used alone; in the case of such failures, STD-causing organisms, if present, may pass from one sexual partner to the other.
Various birth control devices—including barrier methods and vaginal contraceptives—are currently available. Some of these may, in addition, also have a least some degree of anti-STD activity. For example, condoms can help prevent the transmission of STDs so long as they are properly used and/or they perform properly. Nonoxynol-9, currently one of the most widely used contraceptive agents, is reported, at least in some cases, to reduce the risk of transmission of some STDs. Nonoxynol-9, which is a nonionic detergent with strong surfactant properties, acts, like most other chemical-based contraceptives, by killing or otherwise immobilizing spermatozoa (e.g., spermicidal activity). Nonoxynol-9 is a potent cytotoxic agent which tends to nonspecifically disrupt cell membranes. These properties, however, give rise to some very significant disadvantages. Because nonoxynol-9 is strongly cytotoxic, it can injure vaginal/cervical epithelial and other cells at concentrations as low as about 0.0005 percent. Clinical studies have confirmed epithelial disruption of the vagina and cervix. Nonoxynol-9 also disrupts the normal vaginal flora which provides a protective mechanism, perhaps by maintaining a low pH, to guard against the invasion of pathogenic microbes. Nonoxynol-9 may also partially dissolve or remove the protective glycoprotein coating in the vagina. The cytotoxic, flora-disruptive, and glycoprotein-removal effects of nonoxynol-9 can lead to vaginal damage or Injury, including lesions. Some women are especially sensitive to nonoxynol-9 and manifest these effects with only occasional use. The disruption of these protective mechanisms by nonoxynol-9 can actually increase the risks of STD since the breakdown of the protective mechanisms, and especially the occurrence of lesions, allows STD-causing organisms an easier pathway into the cells. Thus, any anti-STD activity of the contraceptive may be reduced or even lost (i.e., overwhelmed) by the increased risk of infection due to physical damage from the contraceptive. Even if such a contraceptive method provided some degree of STD protection, it would, of course, mainly be directed at heterosexual relationships in which pregnancy was not desired.
More recently contraceptives having anti-STD activity have become available. U.S. Pat. No. 5,925,621 (Jul. 20, 1999), U.S. Pat. No. 5,932,619 (Aug. 3, 1999), U.S. Pat. No. 6,028,115 (Feb. 22, 2000), and U.S. Pat. No. 6,239,182 (May 29, 2001) provide methods for the reduction of sexual transmitted diseases using inhibitory agents such as phosphorylated hesperidins, sulfonated hesperidins, polystyrene sulfonates, substituted benzenesulfonic acid formaldehyde co-polymers, H2SO4-modified mandelic acids, and the like.
It would be desirable, therefore, to provide more effective anti-microbial agents and methods for preventing or reducing the risk of sexually transmitted infections and/or diseases; preferably such anti-microbial agents would also be contraceptive and, thus, prevent or reduce the risk of unplanned pregnancies. It would be desirable if such anti-microbial agents, whether contraceptive or not, and methods would not interfere with the natural and protective vaginal mechanisms. It would also be desirable if such anti-microbial agents, whether contraceptive or not, and methods would be relatively easy to use, have significantly fewer side effects than currently available methods (i.e., nonoxynol-9) so that it would more likely be used on a consistent basis, and be effective at lower concentrations. It would also be desirable if such anti-microbial agents, whether contraceptive or not, and methods could be used in heterosexual, homosexual, and bisexual relationships and for a wide range of sexual activities. It would also be desirable if such anti-microbial agents, whether contraceptive or not, and methods could be implemented by either party to the sexual activity. The present invention, as detailed in the present specification, provides such anti-microbial agents and contraceptive anti-microbial agents and methods.